The general purpose of this invention is to provide a lightweight, portable, warm, comfortable, weather-tight, and insect-free bed and shelter for hikers and campers by means of combining a hammock, sleeping bag, and tent and incorporating new features of construction therein. The specific advantages of this invention are (a) improved warmth of that part of the sleeping bag under its occupant, while conserving other normal thermal qualities; (b) better protection of the occupant against wind, rain, snow, dew, ground dampness, insects, rodents, and other small animals; (c) a more level and normal sleeping position for the occupant; (d) improved stabilization aimed at preventing overturning; (e) means for separating the tent portion of the combination when its use is not required; (f) means connected to the device for storing personal possessions and camping supplies above ground for the convenience of the occupant and for protection against dampness, insects, and animals; (g) the full range of these advantages at less overall weight of equipment than normally found under current methods; and (h) the full range of these advantages in a larger size to accommodate two persons.
Hikers, campers and others faced with living out of doors and with the need to provide lightweight equipment for sleeping and shelter have for years wrestled with the problem of how to obtain maximum warmth as well as protection for themselves and their beds from rain, dew, ground water, cold, insects, and small animals. This is especially true for persons who hike long distances while carrying everything necessary for comfort and survival. Veteran campers have repeatedly said that camping is never comfortable unless one has a dry, warm, and restful bed.
Achievement of these basic objectives has always been less than satisfactory. For years campers have carried blankets or comforters such as those used at home, in which they rolled themselves for sleep as best they could. When sleeping on the ground a common method in the early days of this country was to construct a bed of balsam branches, leaves, or other vegetation which would tend to conform to the human body while at the same time providing some insulation from the ground's dampness and coldness. This method was never sufficient to the need and in present times such materials, even when available, are quickly exhausted if used by large numbers of campers. But now, as then, it is not uncommon for a camper to excavate the ground slightly to make the surface thereof conform somewhat to body contours.
The sleeping bag
While the above practices may yet be followed when possible and desirable, four major developments have taken place over the years to assist the camper in obtaining a better bed in the wilderness. The first was the advent of the sleeping bag, which, by utilizing zippers and other fasteners, helps to prevent the excessive escape of body heat from around the sleeper and at the same time to minimize the entry of cooler air from outside. The sleeping bag, however, does not provide comfort in terms of avoiding hardness, uneven surfaces, cold, insects and rodents. For example, the weight of the human body so compresses the material under the sleeper that much of its insulating potential is lost with resultant loss of body heat to the ground.
The air mattress and foam pad
The second development was the introduction of the air mattress and foam pad for use under the sleeping bag. The air mattress has provided some of the comfort of a mattress as commonly used on a bed, and, to a lesser extent, the qualities of an insulator against cold. As experts in this field have pointed out, air mattresses are not fully reliable and sometimes lose pressure during the night. Furthermore, their insulating qualities are limited due to heat transfer by convection within the air mattress itself, again resulting in the loss of body heat. Because of these disadvantages, as well as weight and bulk, most hikers will not carry an air mattress. Foam pads of sufficient thickness provide a measure of reliable softness and insulation but are bulky and heavy.
Insulating materials for sleeping bags
The third major development was the utilization of new synthetic materials for insulating sleeping bags. Some of these provide good insulating qualities, although weight is still a factor. Goose down, long used in bedding, continues to be preferred because of its lightness and superior insulating properties, especially for backpackers. But regardless of the kind of insulating material employed, it all compresses tightly under the weight of the sleeper with consequent severe loss of thermal protection.
Tents for protection from inclement weather
In addition to the problems just described, the outdoorsman encounters wind, rain, and snow, from which his bed must be protected if it is to serve its intended purpose. Tents universally supply this need and over the centuries have been constructed first of skins, then of vegetable fibers. Now they are usually constructed of lightweight synthetic fibers, which constitute the fourth major development. For backpackers, where weight is an important factor, very small tents are used. The hard ground below the tent floor remains the surface on which a sleeping bag must be extended, at least for backpackers, and leakage of ground water into the tent is commonly experienced from prolonged rain or melted snow. Moreover, repacking such a tent after resting on muddy ground always constitutes an inconvenience. The anchoring of tents has continued to be a problem, and upset and ripping of tents by heavy wind continues to plague campers and risk their comfort and well-being.
Use of ground sheets in lieu of tents
When a tent is not carried the camper is usually required to provide an impermeable ground sheet to protect his bed against ground water. Sometimes it is wrapped around the sleeper to give temporary and usually insufficient protection from rain and cold. Sometimes a tarpaulin is laid or stretched beneath the sleeper, with the same limited usefulness. Although now usually made of new, lightweight materials, this equipment nevertheless adds to the weight to be carried. Also, sleeping on the ground leaves a person vulnerable to crawling insects and rodents, which is only partially eliminated even when floored tents are used.
Summary of present conditions
The conditions thus described represent the current state of the art of shelters and beds for outdoorsmen, especially backpackers. In terms of warmth, comfort, weight, and protection from rain, snow, insects, and animals, existing equipment has significant defects. These shortcomings not only constitute important limiting factors to the comfort and enjoyment of hikers and campers in wilderness areas, but are sometimes critical to their very survival. Sometimes deliberate risks are taken because of weight limitations and certain important items of equipment are left behind. Unanticipated bad weather, for example, may spoil an excursion when adequate rain shelter has not been included. Clearly, lighter and more efficient equipment would reduce these problems and enhance the pleasure and safety of backpacking and camping.
The use of hammocks
Although the sleeping problems of the camper/hiker have been studied over the years, relatively little attention has been given to the hammock as a potential solution for many situations despite the long and satisfactory use of that type of bed in certain regions and under specific conditions. For example, hammocks have been used aboard ships for many centuries. In some tropical regions of the world today, such as Yucatan, Mexico, it is the preferred method of sleeping for the majority of the population. Double hammocks, accommodating two persons, are also common there. The U.S. Army developed a hammock for use in tropical areas, together with mosquito net and cover against rain. The advantages of hammocks over sleeping on the ground or floor have been recognized in a number of instances.
Hammocks in the temperature zones. Nevertheless, in the temperate and colder zones, hammocks have not seriously competed with sleeping bag/air mattress and sleeping bag/foam pad combinations. A major drawback has been the lack of warmth in existing hammock construction. Also militating against widespread use of hammocks in the United States has been their general discomfort for sleeping, wherein the body must generally remain in a curved position, resting mostly on the back, and discomfort becomes readily apparent after relatively short periods of time. This problem stems from the way in which most hammocks are constructed, which construction differs markedly from the design of net sleeping hammocks used in the tropics.